Conventional methodologies often fall short in accommodating the unique requirements of assistive devices, which intimately interact with the human body. To address these intricacies, this paper presents an innovative framework that combines Nigel Cross' methodology with Human-Centered Design. This integration enriches the design process by infusing empathy, user involvement, and iterative prototyping.While promising, the paper acknowledges limitations, including its application to a single case study of an upper limb prosthesis and the challenges of adapting the methodology to products of varying complexity. In essence, this paper contributes a holistic methodology that addresses the unique challenges of designing assistive devices, fostering innovation through user-centered and multidisciplinary collaboration.